This invention relates to a motor control apparatus combined with an engine, particularly to a motor control apparatus combined with an engine having an automatic start-up/stop control means for start-up, which is disposed in a vehicle having the engine and an electric motor disposed therein as a vehicle-propelling system. The motor is combined with a crank shaft of the engine, and has both driving and power-generating functions.
Some motor vehicles are of a type commonly called a hybrid vehicle having an internal combustion engine and an electric motor (referred to as xe2x80x9cmotorxe2x80x9d throughout the specification) disposed therein as the power sources of a propulsion system. The motor disposed in the hybrid vehicle is combined with the engine, and the hybrid vehicle further includes an engine control means for controlling a running state of the engine and a motor control means for controlling an operating state of the motor. The engine control means and the motor control means detect respective operating states of the engine and the motor when the vehicle is traveling, and then exchange such detected data regarding the running states. As a result, the respective operating states of the engine and the motor are controlled in association with one another. Such a control system attains a high level of required performance (such as fuel efficiency, lower values of detrimental components in exhaust gases, and power performance).
One such example of a control apparatus for a motor combined with an engine is disclosed in published Japanese Application Laid-Open No. 8-93517. The hybrid electric powered vehicle includes a power generating apparatus driven by an engine and a battery for powering the vehicle. The vehicle includes a motor that can receive electric power supplied from the battery, or the power generating apparatus can supply electric power to the battery. An electronic control apparatus for controlling the motor is powered by a sub-battery. The electronic control apparatus includes a means for determining that the engine is started, a means for prohibiting driving of the starter by electric power from the sub-battery during control of the motor after the engine is determined to have started and a means for determining whether a terminal voltage of the sub-battery is less than a predetermined voltage. As a result, the control means prevents a false movement of an electronically controlled apparatus due to a drop in voltage of the sub-battery during a restart operation for the engine.
Published Japanese Patent Application Laid-Open No. 10-136508 discloses a hybrid vehicle that has an engine operated by combustion energy of fuel and an electric motor operating by electric power from a power source in the vehicle. The vehicle has a starter for start up, and usually is started by cranking an engine with the electric motor. But, the hybrid vehicle has an engine start-up control means to start cranking the engine with the starter when a start-up by the electric motor is determined to be impossible. Then engine start-up control means has an additional function to assist in cranking the engine when the hybrid vehicle starts cranking an engine with the starter. In this way, the hybrid vehicle suitably starts up the engine by using the small and cheap starter.
In published Japanese Patent Application Laid-Open No. 6-257484, the engine automatic start-up/stop apparatus controls start up of an engine when a predetermined start-up condition is satisfied after the engine disposed in a vehicle is stopped, and also stops the engine when a predetermined stopping condition is satisfied during running of the engine. In the engine automatic start-up/stop apparatus, when a predetermined time condition passes while a stop mode is continued after the engine is started up by an operation of an engine-key, and a following stopping condition when the vehicle moves, satisfying a condition, then the engine is automatically stopped. The automatic start-up/stop apparatus makes automatic shutoff of an engine possible when the temperature is low, and improves mileage when a driving time is comparatively short.
Published Japanese Patent Laid-Open No. 10-47104 discloses an engine automatic start-up/stop apparatus which is controlled so as to automatically stop when a predetermined automatic stop condition is satisfied during running of an engine disposed in a vehicle, and is controlled to automatically start up when a predetermined automatic start-up condition occurs after being automatically stopped. The engine automatic start-up/stop apparatus determines whether the vehicle is started up by the engine-key when the engine is started up, and whether the vehicle is started up after automatically being stopped, and can change the initial value of a revision quantity of an idle air flow quantity at a key start-up mode and the initial value at an automatic start mode.
The engine automatic start-up/stop apparatus prevents an unnecessary rise of an idle speed in automatically starting-up the vehicle after automatically being stopped, and improves the mileage.
A control means of a motor combined with an engine is used for a so-called idle-stop vehicle. The idle-stop vehicle is restarted by a starter motor after the engine is stopped.
If using the starter motor to restart, when the starter motor is engaged with a ring gear, an inconvenience occurs from a noisy sound. There is also inconvenience in that the durability of a starter motor is decreased.
When the engine is restarted, a starting-up compensation acts, and it can become unnecessarily rich in fuel to maintain a rise of engine speed. As a result, there is inconvenience in that more fuel is used than needed. Further, an exhaust gas containing harmful ingredients in unnecessary abundance is exhausted. When a restart of an engine occurs for a fixed time, additional fuel is desirable for a certain mileage distance and a proper output dispersion of exhaust gas from the engine continues.
In the apparatus disclosed in published Japanese Patent Application Laid-Open No. 10-136508, when cranking by a motor is impossible, then the cranking may be done by a starter. When the cranking is done by the starter, then the motor assists in cranking the engine according to need. In operation of the above-mentioned published Japanese Patent Application Laid-Open No. 10-136508, inconvenience occurs from noisy sound when a starter gear is engaged.
In order to obviate the above problems, the present invention provides a motor control apparatus combined with an engine and an electric motor in a vehicle-propelling system. The motor is connected to a crank shaft of the engine and has both driving and power-generating functions. An automatic start-up/stop control means includes automatic start-up control and automatic stop control sections. The start-up control section starts the vehicle using the starter motor while always receiving assistance from the motor when the vehicle is started with a key. The automatic start-up control section automatically starts up the motor, which cancels noisy sounds occurring when a ring gear engages a starter motor gear. This improves quietness, which characteristic is advantageous in practical use. Further, improved characteristics for discharge of exhaust gas result.
According to the present invention as previously described, at automatic start-up, the control means controls a vehicle start up automatically using only the motor and cancels noisy sounds occurring when a ring gear engages with a starter motor gear. As a result, the quietness is improved, better dispersion of the exhaust gas is expected, and a simplification of the system results.